Copying machines provided with such paper handling devices as mentioned above are disclosed in Japanese Patent Laid Open Publications No. 59-43765, No. 60-183461 and No. 60-248563. This type of paper handling device provided for copying machines is usually called a finisher and is constructed so that copied papers are stored and aligned in a tray and transported to a stack unit to be stacked after being stapled. Regarding the tray of the finisher, the type of tray which enables the papers to be substantially vertically stored therein for saving space and for the convenience of sheet alignment has been developed.
In a stapling operation with the use of said finisher, a manual stapling, which is a mode enabling an operator to staple freely by pressing a stapling key, can be selected. During an operation in the manual stapling mode, if an operator leaves the place in the middle of the stapling process or if an operator forgets to press the stapling key to execute a stapling operation although the papers are stored and aligned in a stapling tray, the papers will be left in the stapling tray. After that, if another operator executes an stapling operation, a trouble will occur such as mixing the papers currently to be stapled with the papers left therein by the last operator and stapling all together. Also, such a trouble is apt to occur when the papers stored in the stapling tray can not be recognized or hard to be recognized from outside. Further, when a power switch is turned off while keeping the papers in the stapling tray without being stapled, the papers may be forgotten to be ejected from the stapling tray. When another operator turns on the power switch again and proceeds to the stapling operation, a trouble that the papers currently to be stapled are mixed and stapled together with the papers left behind by the last operator may occur.